Supply network planning (SNP) computer-modeling applications are used to plan out the production, or manufacturing, process for a product. SNP computer-modeling is typically only performed once a design for the product is finalized and all necessary specific component parts have been chosen. The planning horizon is usually from six to eighteen months, or even longer. The planning parameters used are usually not constant during the planning horizon. The changing values of planning parameters may adversely affect the quality and accuracy of the SNP runs over time.
An example of the changing values of these planning parameters is illustrated in the graph of FIG. 1. As shown in FIG. 1, when a new semiconductor product is introduced for production, the beginning yield rate is usually low. Then upon mastering the production process used, the yield rate may improve significantly over time. The targeting yield rates may change quarterly or even monthly. Therefore, using a fixed value representing the yield may adversely affect the ability of planners to properly forecast needed supplies or materials due to over-planning or under-planning.